This circuit board was originally designed to connect parallel to the power- and resetbuttons of PCs, to be able to turn them on, off, and reset them via another PC.
This circuit board is equipped with 4 or 8 optocouplers, so is able to switch 4 or 8 different signals. 4 or 8 LEDs are mounted, to signal whether the connector to the PC is connected right, or if the polarity is reversed.
Of course, it's perfectly fine to switch other signals with this PCB.
Of course, your PCB will have 16-pin IC sockets, instead of modified 18-pin sockets.